Disposable diapers provide substantial advantages in convenience over diapers intended to be laundered and reused, particularly when they are used away from home. In recent years, many different disposable diapers have been proposed and some have been successful in the marketplace. Typical disposable diaper structures comprise a facing material to be brought into contact with the infant's skin, an absorptive layer of high liquid-holding capacity, and a moisture-impervious backing layer, generally made of a plastic film such as a polyethylene film. Typical disposable diaper structures are shown in U.S. Pat. No. 3,612,055 to Mesek et al. and in U.S. Pat. No. Re. 26,151 to Duncan et al.
As may be seen from the above-cited patents, it has been desired to obviate the problems that are inherent in closure systems utilizing extraneous fasteners such as safety pins, snaps and zippers. To this end, adhesive closure systems have presented acceptable solutions.
One of the most convenient adhesive systems that has been developed to date is the system, shown in the above-cited patents, in which adhesive tabs are adhered to the backing sheet extending outwardly from opposite sides of the diaper at one end thereof, with the exposed areas of the adhesive strips having cover strips thereon that are readily separable from the adhesive tabs. Disposable diapers using an adhesive closure system of this general type have the disadvantage of requiring the consumer to dispose of the cover strips when they are separated from the adhesive strips. This is an inconvenience to the consumer who is placing the diaper on an infant.
An illustrative prior art adhesive system having cover strips permanently attached to the diaper is disclosed in U.S. Pat. No. 3,646,937 to Gellert. The Gellert arrangement has the disadvantage of having the release film on the inside of the diaper, where it can possibly come in contact with an infant's tender skin. Additional disadvantages are the complexities and expense which are added to the manufacturing process by requiring each adhesive closure to be manipulated on the front side, around the edge, and on to the back side of the diaper, instead of handling it on one side only. The closure system illustrated in the Gellert patent also makes it somewhat difficult to secure the diaper around an infant, in that it requires the use of two hands to peel back the releasable end of the adhesive tape.
U.S. Pat. No. 3,853,129 to Kozak attempts to solve the foregoing problems by providing adhesive tabs having a fixed end segment attached to the diaper, a middle segment having one face covered with a mesh-like plastic material defining a system of hill portions and valley portions, and a releasable working end coated with a pressure-sensitive adhesive and releasably adhered to the hill portions in the middle segment. However, with such an arrangement the available effective adhesive area is limited, the working end of the tab may be subject to displacement transverse to the longitudinal axis, and the tab could be subjected to greater stresses when in use than when the fixed end and the working end of the tab are contiguous.